It is hard to believe that she's only nine.

很难相信她只有九岁。

《牛津词典》

It seems hard to believe that we can deal with more serious diseases yet are powerless against something so common as a cold.

让人难以相信的是，我们能够治疗更严重的疾病，却无力对抗像感冒这样常见的疾病。

youdao

It is hard to believe that he used to have many problems in school.

很难相信他曾经在学校遇到过很多问题。

youdao

Rudolf found it hard to believe that there was someone in the world who did not know what violin was.

VOA: special.2010.05.08

Now, I think that ultimately--interestingly enough, Los Angeles had a real estate boom and bust in the 1880s; that's hard to believe.

现在,我认为这非常有意思,19世纪80年代洛杉矶经历了房地产的,繁荣和萧条,这难以置信

耶鲁公开课 - 金融市场课程节选

But that seems very hard to believe ? I mean, when I'm dead, I don't exist, right?

但那又似乎太难以让人信服了,我是说，当我死了的时候，我不存在，不是吗？

耶鲁公开课 - 死亡课程节选

Sometimes it was hard to believe that we would ever get things moving again.

UNESCO: UK National Commission for UNESCO - Stars in their mines: Cornwall mining community makes it big in Hollywood

"She found it hard to believe that these could be hospital documents, " he said.

BBC: Sensitive medical records found in Londonderry garden

It is hard to believe that recent events would not have further eroded European consumer sentiment.

FORBES: Has A Serious Mobile Phone Slump Started In Europe?